HVAC components

Climate control UI for multi-zone cabins: temperature, fan, modes, seat heat / vent, and visibility-critical actions (defrost).

Purpose

• Fast, low-distraction adjustment of climate.
• Clear zone ownership (driver / passenger / rear).
• Keep defrost and visibility actions available and obvious.

Component set (planned)

Component	Role	Safety class
HvacZonePanel	Temp + fan for a zone	Convenience
HvacTempStepper	Large ± temperature	Convenience
HvacFanControl	Fan level / auto	Convenience
HvacModeSelector	Face / foot / bi-level / etc.	Convenience
HvacSeatClimate	Heat / vent levels	Convenience
HvacDefrostControls	Front/rear defrost	Safety-critical (visibility)
HvacSyncToggle	Sync zones	Convenience
HvacPeek	System bar shortcut	Convenience

States

• Auto vs manual
• Sync on/off
• Seat climate levels
• Defrost active
• HVAC power off (still show how to power on with large target)
• Signal unavailable per zone

Compliance

Concern	Rule
Driving	Stepper and toggles allowed; deep HVAC settings may be limited (driving)
UX	Large steppers; generous spacing (ux)
Safety	Defrost always reachable; not behind setup (safety)
Glance	Numeric temp tabular; zone labels short

Token dependencies

• cabin.color.semantic.climate
• cabin.component.hvac.zone.gap
• cabin.component.hvac.stepper.minSize
• Touch minima tokens

Planned Compose API

// Planned
@Composable
fun HvacZonePanel(
    zone: HvacZoneUiState,
    onChange: (HvacZoneAction) -> Unit,
    modifier: Modifier = Modifier,
)

@Composable
fun HvacDefrostControls(
    state: DefrostUiState,
    onChange: (DefrostAction) -> Unit,
    modifier: Modifier = Modifier,
)

Planned Views API

<!-- Planned -->
<dev.decoupled.cabin.views.hvac.HvacZonePanelView
    android:layout_width="0dp"
    android:layout_weight="1"
    android:layout_height="match_parent" />

Parity notes

Zone models and defrost latched states must match. Animation of temp changes should respect driving motion budgets on both stacks.

Acceptance criteria

• Defrost classified and always available
• Zone panels meet touch minima
• Unavailable zone signals handled
• Sync behavior documented
• Compose/Views parity for temp/fan/defrost

Related

• System bars (HVAC peek)
• Vehicle controls
• Safety-critical